I was going to say stationery, but these youth of today don't write letters, they email.
Bath and Body Works really isn't makeup, so that might be good. (I've never met a girl who doesn't like bubbly bath stuff.)
Harry Potter - see if they have any figurines (like Precious Moments, only H.P.) or something she could sit on her desk. That wouldn't be too juvenile, I don't think.
Jewelry would be good - but not too expensive. Try getting some of the pieces from The Limited or Express - maybe matching necklace & earrings. This isn't outrageously priced, and she will like that it came from a more adult store.